In some mechanical assembliesxe2x80x94such as, for example and particularly, but not exclusively, in telescopic cardan shaft assemblies for transmission of them movementxe2x80x94lubrication is required at several points, using grease injected under pressure.
For the sake of operational practicality, in order to ensure lubrication at all the required points, lubrication systems have been envisaged, comprising a single grease nipple from which several points to be lubricated are supplied. These systems do not ensure uniform lubrication at all the points, use an excessive amount of lubricant and also disperse an excessive amount thereof, as well as having other drawbacks which make them unreliable, although being relatively complex and costly.
The object of the invention is to provide a simple and reliable lubrication system, as will emerge from the text which follows.
According to the invention, the grease lubrication system comprises essentially a chamber supplied by a greasing unit, several branched channels which reach the points where the lubricant is to be supplied, and, between said chamber and each branched channel, a passage with a very small cross section. In this way, a high pressure is reached inside said chamber with injection through the grease nipple and a metered supply of lubricant through each of said passages is thus obtained.
The system in question is particularly suitable for the lubrication of telescopic and cardan shafts for transmission of the movement, mainly used in vehicles, machine tools, agricultural machines and the like.
In a telescopic shaft with grooved tubular shafts, the lubrication system may comprise, in the internal shaft, a first block with the seat for the grease nipple, with said chamber and with seats for several pipes forming part of said branched channels, and in said block said passages with a small cross section are also formed. Said internal shaft also houses at least one terminal block, which is supplied by at least one or more than one of said pipes and which also houses one or more radial tubular pins, each communicating with a corresponding pipe and emerging from the internal tubular shaft at the points where lubrication is required. Basically, the terminal block may be supplied by several pipes and houses respective tubular pins which are radially distributed.
The or each terminal block may be engaged with the internal tubular shaft by means of the tubular pin or pins. Said first block may also be engaged with the internal tubular shaft by means of the greasing unit which can pass through the external tubular shaft via a terminal recess.